Enforce unsafe_op_in_unsafe_fn

[Veykril]

We'll need to do this for the 2024 edition upgrade. The motivation for this change thouhgh is so I can quickly check whether the merge queue works now (and so I'll self approve this)

[netlify]

✅ Deploy Preview for salsa-rs canceled.

Name	Link
🔨 Latest commit	68e26c0
🔍 Latest deploy log	https://app.netlify.com/sites/salsa-rs/deploys/67b98da715ecb0000839959b

[codspeed-hq]

CodSpeed Performance Report

Merging #713 will not alter performance

_{Comparing Veykril:veykril/push-rtrowyplmxzw (68e26c0) with master (70a0172)}

Summary

✅ 9 untouched benchmarks

[MichaReiser]

We'll need to do this for the 2024 edition upgrade.

Is my understanding correct that an 2024 edition upgrade would require bumping the MSRV to 1.85? Bumping the MSRV is technically a breaking change for Ruff because users can build Ruff from source. That's why we try to only bump the MSRV when necessary.

[Veykril]

Yes it would require 1.85 (or later). I didn't mean to imply we should do that ASAP (though I think Niko would love 1.86 for trait upcasting).

I do think we want to release 1.0 proper on 2024 edition rules though. The MSRV story is definitely a meeting discussion topic.

[Veykril]

Okay I think the merge queue works now (its blocking on the CI check introduced in #712)